Aspergilli as Ochratoxin Producers

Abstract

To determine whether ochratoxin is produced by species of Aspergillus other than A. ochraceus, 44 strains representative of the nine species composing the A. ochraceus group were grown on both pearled wheat and cracked corn in duplicate shaken flasks at 28 C for 5 days. Rice was a poor substrate for production of ochratoxin. Molded substrates were extracted with acetonitrile-water; partially purified e.'ctracts were assayed for ochratoxins by thin-layer chromatography. All positive samples were confirmed by solubility in sodium bicarbonate and the preparation of methyl esters. Ochratoxins A and B were found in some strains of A. SlllphllrC1ls, A. sc/erotiorum, A. alliaceus, A. melleus, A. ochracells, A. ostian/Is, and A. petrakii. No ochratoxin was produced by the one strain of A. elegans or any of six strains of A. auricomtls. Five of nine strains of A. sclerotiorum and five of 11 strains of A. ochracells were negative. All seven strains of A. alliaceus were positive, but one was at a very low level. Generally, yields of ochratoxin were higher in wheat than in corn. Occasionally, as much ochratoxin B was produced as A. Highest yields of ochratoxins A and B were obtained from respective strains of A. ochracetls NRRL 3174 and NRRL 3519. Some strains of most species of the A. ochraceus group produce this mycotoxin as a secondary metabolite. I CH 3 CI Van der Menve et al. (l965a) described three types of ochratoxin designated as A, B, and C. Ochratoxin A is 7-carboxy-S-chloro.:8-hydroxy-539 Putl".d bJ U. S.~pt. of AgrlsdtlUe for Official Use

Ochratoxin A: General Overview and Actual Molecular Status

“…In Aspergillus section Circumdati (formerly the Aspergillus ochraceus group), the following species can produce OTA: Aspergillus cretensis , A. flocculosus , A. pseudoelegans , A. roseoglobulosus , A. sclerotiorum , A. sulphureus and Neopetromyces muricatus [59]. According to Ciegler [70] and Hesseltine, et al [71] A. melleus , A. ostianus , A. persii and A. petrakii may produce trace amounts of OTA, but this has not been confirmed since publication of those papers. Strains of these species reported to produce large amounts of OTA were re-identified by Frisvad et al [72].…”

Electrochemical Aptasensor for the Determination of Ochratoxin A at the Au Electrode Modified with Ag Nanoparticles Decorated with Macrocyclic Ligand

“…Ochratoxin A (OTA) (Scheme ) is a secondary metabolite produced by filamentous fungi of the genera Aspergillus and Penicillium present in a wide variety of foodstuffs, e.g., cereals, coffee, cocoa, grapes or spices. Due to the OTA stability, it is also frequently found in processed food, e.g., bread, beverages, and wine 1, 2. OTA exerts nephrotoxic, carcinogenic, teratogenic, immunotoxic and hepatotoxic effects and can probably cause nephropathies and urothelial tumors in humans 3, 4.…”

OTA-producing fungi in foodstuffs: A review

“…Other fungi able to produce OTA are: Petromyces alliaceus (Lai, Semeniuk, & Hesseltine, 1970), Aspergillus sulphureus (Hesseltine et al, 1972); Penicillium verrucosum (Pitt, 1987); Aspergillus niger (Abarca, Bragulat, Castellá, & Cabañes, 1994), Aspergillus carbonarius (Téren, Varga, Hamari, Rinyu, & Kevei, 1996), Penicillium nordicum (Larsen, Svendsen, & Smedsgaard, 2001), Aspergillus lacticoffeatus and Aspergillus sclerotioniger , Aspergillus cretensis, Aspergillus flocculosus, Aspergillus pseudoelegans, Aspergillus roseoglobulosus, Aspergillus westerdijkiae, Aspergillus sulphurous, Neopetromyces muricatus and Aspergillus steynii .…”

“…and Penicillium (P.) present in a wide variety of foodstuffs (Hesseltine, Vandegraft, Fennell, Smith, & Shotwell, 1972) such as cereals, coffee, cocoa, grapes or spices and, due to OTA stability, in processed products such as bread, coffee beverages, chocolate or wine (Miraglia & Brera, 2002). This mycotoxin has been described as nephrotoxic, carcinogenic, teratogenic, immunotoxic and hepatotoxic in laboratory and domestic animals, as well as the probable causal agent in the development of nephropathies and urothelial tumours in humans (O'Brien & Dietrich, 2005).…”